Drying apparatus for flexible supports

ABSTRACT

An apparatus for drying a flexible support having cylindrical air chambers with air inlets and air outlets for supporting the support as it moves in a helical path around the air chambers and air cushion roller means arranged such that the helical path of the support and the path of the support around the roller is substantially equivalent to the plane tangent of both paths.

United States Patent [72] Inventors Motoharu Kuroki [56] References Cited Akira Takagl. Kanagawa, Japan UNITED STATES PATENTS AP 836726 2070,252 2 1937 Borner 34/152 [22] Flled June 26,1969

2,532,562 12/1950 L0r1g.... 34/l53 Putemcd 1971 2 659 225 11/1953 Ewing 34/153x z I Awgnee g'gi' i gfi g 3,125,268 3/1964 Bartholomay 226/97 [32] Priority y 18 1968 3,303,576 2/1967 S1 ss0n 34/115 [33] Japan Primary Examiner-Martin P. Schwadron {3 l 1 50,666/68 Assistant Examiner-Theophil W. Streule Attorney-Sughrue, Rothwell, Mion, Zinn & Macpeak [54] DRYING APPARATUS FOR FLEXIBLE SUPPORTS 7 Chums Drawmg Flgs' ABSTRACT: An apparatus for drying a flexible support hav- [52] U S Cl H 1 5 115, ing cylindrical air chambers with air inlets and air outlets for 34 5 supporting the support as it moves in a helical path around the 511 Int. Cl F26b 13 20 air chambers and air Cushion rallfir means arranged Such that [50] Field of Search ..226/(lnquired); the helical path of the support and the path of the support 197/( Inquired 242/( inquired around the roller is substantially equivalent to the plane tangent of both paths.

PATENTEB JAN26 I971 sum u {1F 6 I PATENTEU JAN26I97I ,5 7

sum 5 BF 6 PATENTEU JAMES IBTI SHEET 6 OF 6 DRYING APPARATUS FOR FLEXIBLE SUPPORTS BACKGROUND OF THE INVENTION Field of the Invention This invention relates to a drying apparatus for continuously drying elongated flexible supports such as papers. plastic films and the like. and in particular to a drying apparatus for concretely and effectively carrying out the drying method described in our U. S. Pat. application No. 711,239 entitled Process for Drying Pliable Supports." filed on Mar. 7. 1968 now U.S. Pat. No. 3.481.046 granted Dec. 2. I969.

In our aforesaid patent there is disclosed a method for continuously drying an elongated flexible support. It is particularly'cffective for drying a support having solvent-containing coating layers. According to the invention disclosed in our aforesaid patent, a continuously moving flexible support can be dried without any contact with solid surfaces during the drying step. whereby the drying is carried out more effectively and economically.

As an embodiment for carrying out the drying method, an apparatus as shown in FIG. 16 is disclosed in our aforesaid patent. In such an apparatus, however, the support is not stably conveyed but is apt to flutter in the portion between one cylindrical air chamber and another. Further. the adjacent air chambers are not disposed parallel to each other as shown in FIG. I6 which is a disadvantage in that more space is required.

This invention provides a drying apparatus for an elongated flexible support which eliminates the disadvantages above mentioned in carrying out the drying'method of our patent.

SUMMARY OF INVENTION An object of the present invention is to provide a drying apparatus for a flexible support which is smaller in size than that used in carrying out the method of our aforesaid patent.

Another object of the present invention is to provide a drying apparatus for a flexible support which conveys the support stably while carrying out the above drying method.

Still another object of the present invention is to provide a drying apparatus which varies the drying conditions such as the temperature and humidity of the drying air and also the blowing velocity of the air directed onto the support stepwise with the advance of the drying process.

Additional objects will be apparent from the following description of the invention.

The drying apparatus of this invention comprises at least one cylindrical air chamber having at least one air inlet and a plurality of air blowoff holes for supporting an elongated flexible support on an air cushion which moves continuously around the air chamber through a helical passage, and at least one air cushion roller arranged in the .vicinity of the air chamber, the air cushion roller being so arranged that the passage of the support in the area where the support is bridged between the helical passage around the air chamber and the passage around the air cushion roller is substantially equivalent to the plane tangent to both of said passages.

The cylindrical air chamber is provided in the cylindrical surface thereof with a plurality of air blowoff holes and at the end face or at the portion of its cylindrical surface away from the passage of the support, one or more air inlets. The air blowoff hole mentioned above is an opening in the shape of a circle, a slit or, the like. If desired, the air supplied into the air chamber through the air inlet can contain other gaseous components and the temperature and humidity thereof can be suitably controlled.

The above-mentioned air cushion roller is similar to those used in the prior art which supports the support on an air cushion and which can change the advancing direction thereof without touching the support.

The invention will now be described with reference to the accompanying drawings in which:

FIG. I is an elevational view of the drying apparatus in accordance with the present invention;

2 FIG. 2 is a cross-sectional view taken along the line IIll of FIG. I:

FIG. 3 is a side view of the drying apparatus shown in FIG.

FIG. 4 is a perspective view of the drying apparatus shown in FIG. 1;

FIGS. 5, 7. 9. I I and 14 are plan view of'otlier embodiments ofthe present invention;

FIG. 6 is a partial elevational view ofthc apparatus shown in FIG. 5: I

FIG. 8 is a schematic side view of the apparatus shown in FIG. 7;

FIG. 10 is a view of the apparatus shown in FIG. 9 viewed from the direction shown by the arrows X-X in FIG. 9;

FIG. I2 is a view of the apparatus shown in FIG. 11 viewed from the direction shown by the arrows XII-XII in FIG. II;

FIG. 13 is a side view of another embodiment of the present invention;

FIG. 15 is a side view of the apparatus shown in FIG. I4;

and

FIG. 16 is a plan View of an embodiment of our copending application which is not in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIGS. 1 through 4 showing an embodiment of the present invention which comprises one cylindrical air chamber and one air cushion roller. a cylindrical air chamber 1 is provided with a plurality of air blowoff holes 4 in the cylindrical surface 6 and is provided with an air inlet 5 at an end face 7 thereof to which an air duct I1 is connected. The air which has been purified and controlled to the temperature'and humidity conditions required in the'dry-ing process by means of an ordinary drying air source (not shown) such as blowers. filters. heaters. dehumidifiers and the like is supplied through the air duct 11 and the air inlet 5 into the air chamber 1.

As shown in FIG. 2, the air supplied into the air chamber 1 is blown off through the blowoff holes 4 into the air cushion spacing 8 between the support 3 and the cylindrical surface 6 of the air chamber 1. After performing effective drying, the air is diffused into the atmosphere through the gap 9 between the helical turns of the support 3. If desired. it is possible to recollect the diffused air by using some, adequate air collecting device in order to reuse the air again for drying.

The passage of the Support 3 will now be described hereinbelow. For simplicity. the air blowoff holes on the cylindrical air chamber are omitted in the drawings, FIG. 4 and thereafter. The segment ofa line ab shown in FIGS. 1. 3 and 4 is a segment of a line in the helical passage which is parallel to the generating line of the cylindrical surface of the air chamber. and the curved surface cafe is a support passage wherein the advancing direction of the support 3 is changed on an air cushion along the air cushion roller 2. which is called the passage around the air cushion roller. The figure abdc is a plane-quadrilateral which is tangent to the helical passage at 5 and to the passage around the air cushion roller at That is, the plane including the quadrilateral abdc is a common tangent plane to both of said passages. The plane efgl is tangent to the passage around the air cushion roller at ef.

A so-called wet or moist continuous flexible support 3 carrying solvent-containing coating layers or the like which has been fed in the direction indicated by the arrow in FIGS. 1, 3, and 4 by some adequate feeding apparatus (not shown) is wrapped helically around the cylindrical air chamber 1 with the surface to be dried facing internally. The support 3 advancing in the helical passage is supported on the air cushion formed between the support 3 and the cylindrical surface 6.

After the dryirlg process, the support 3 exits from the helical passage at al shown in FIGS. 1, 3 and 4, advances in a passage substantially equivalent to the plane abdcggnters into the passage around the air cushion roller at 9d, and after advancing i n the passage around the air cushion roller exits from it at gf.

The angle (or shown in FIG. I) of the helix of the helical passage is determined by the width of the support 3 and the diameter of the helical passage. This angle should be selected or determined so that each turn of the support 3 may not overlap the adjacent turns and the gap 9 between the adjacent turns may be sufficient to allow escape'ofthe drying air.

The pressure and the flow rate of the drying air supplied into the air chamber I is selected so that the air pressure of the spacing 8 may balance with the tension applied to the support 3 and the weight thereof, and the drying air blown off through the holes 4 may have enough velocity and flow rate to produce effective drying.

The support which exits from the passage around the air cushion roller may be drawn out through a tension roller (not shown) or carried into other processes by a feeding device (not shown).

FIG. 5 illustrates an embodiment of the invention which comprises three cylindrical air chambers I, I, 1" parallel to one another and four air cushion rollers 2, 2, 2", 2 arranged at the support entering portion and exit portion and between the air chambers. The support passage where the support 3 enters and leaves the apparatus is at a right angle with the cylindrical air chambers l, l, 1. And hereinafter, in the embodiments having more than two air chambers, the portion of the support passage where the support enters the apparatus will be called the entering portion, the portion where the support exits the apparatus will be called the exit portion and the portion where the support is conveyed from one air chamber to another will be called the joining portion.

FIG. 7 illustrates an embodiment of the invention which comprises a plurality of cylindrical air chambers l, 1 parallel to each other and three air cushion rollers 2, 2, 2" arranged at the entering portion, the joining portion and the exit portion. In this embodiment, as shown in FIG. 8, the passage around the air cushion roller 2 at the joining portion is directly. connected with the helical passages. That is, this case correspgnds to the special case in which the segment of the line t; in FIGS. 1,3 and 4 coincides with the segment of a line qd FIG. 9 illustrates an embodiment of the invention which comprises three parallel cylindrical air chambers l, l, I" and six air cushion rollers 2, 2', 2", 2", 2"", 2", wherein the support 3 is maintained in horizontal plane at the joining portion. In this embodiment, the time taken by the support 3 to pass around the air chamber 1" is made longer than the time to pass around the air chamber 1 or 1.

FIG. 11 illustrates an embodiment which comprises a plurality of parallel cylindrical air chambers l. I and a plurality of air cushion rollers 2, 2 which can dry both surfaces of the support 3 in series. FIG. 13 illustrates another embodiment which comprises four parallel air chambers l, 1', I", 1" arranged in two rows and has eight air cushion roller 2, 2', 2", 2", 2"", 2", 2, 2". In this embodiment, both surfaces of the support 3 can be dried alternately.

FIG. 14 illustrates an embodiment of this invention which comprises a plurality of parallel cylindrical chambers 1, I and three groups of air cushion rollers 2, 2', 2" and wherein each group of air cushion rollers is arranged so that the passages around them may be directly connected with the helical passage in the same manner as in FIG. 7. In this embodiment, the stability of the support 3 is increased.

As set forth hereinbefore, FIG. 16 illustrates an embodiment of the method used in our copending application which is different than that used in the present invention. Comparing this embodiment with the one shown in FIG. 5, it will be apparent that the device in accordance with the present invention requires considerably less space than that shown in FIG. 16. In the device shown in FIG. 16, the support is apt to flutter at the joining portions because at these portions the drying air rapidly and intensely rushes along the support. On the other hand, in accordance with the present invention, at these joining portions, the support is adequately supported by air cushion rollers, thus the above instability is reduced and the su port can be conveyed smoothly and stably.

t is possible to vary the drying conditions stepwise in relation to the advancement ofthe drying process by supplying the drying air-conditioned differently to the different air chambers from separate air sources in each embodiment of the present invention shown in FIGS. 5, 7, 9, II, 13 and 14.

As can be understood from the above description, in accordance with the present invention, it is possible to make or realize a highly space economical drying apparatus in carrying out the drying method as disclosed in our copending application.

Another advantage obtained by the present invention is that the support can be conveyed stably in carrying out the method in our copending application and the drying condition such as the temperature, humidity, blowing off velocity, flow rate and the like of the drying air can be varied in steps according to the drying process advancement.

Still another advantage of the present invention is that the device can be so constructed that the time for the support to pass over each air chamber can be set to the most adequate length.

One more advantage of the present invention is that both surfaces of an elongated flexible support can be dried alternately or one after another without any contact with the rollers or the like.

The drying apparatus in accordance with the present invention also has such advantages as those detailed in our copending application, that is; (a) the elimination of trouble caused by contact of the support with a solid surface such as guide roller during the drying step of the flexible support; (b) need to use separate air for both supporting the support other than the air used for drying, thus it is economically advantageous; (c) the construction of the device is so simple that everyday maintenance can be easily conducted.

The present invention has been described in detail with particular reference to preferred embodiments thereof, but it is apparent that various modifications and variations can be effected within the scope of the invention as defined in the appended claims:

We claim:

1. A drying apparatus for an elongated flexible support which comprises:

a. at least one cylindrical air chamber having at least one air inlet and a plurality of air blowoff holes for providing an air cushion for supporting an elongated flexible support which moves continuously around said air chamber through a helical passage; and

b. at least one air cushion roller disposed in the vicinity of said air chamber, said air cushion roller being so arranged that the passage of the support where the support is bridged between said helical passage around the air cushion roller is substantially equivalent to the plane tangent to both of said passages.

2. The drying apparatus according to claim 1 wherein two or more air chambers are disposed parallel to one another and air cushion rollers are arranged where the'support enters, joints and exits said air chambers.

3. The drying apparatus according to claim 2 wherein a plurality of air cushion rollers are arranged at each portion where the support enters, joins and exits said air chambers.

4. The drying apparatus according to claim 2 wherein-the drying air is conditioned differently for each of said air chambers.

5. The drying apparatus according to claim 2 wherein the diameters and the lengths of the air chambers are different from each other. i

6. The drying apparatus according to claim 2, wherein the passage of the support is so formed that both the surfaces of said support are dried alternately.

7. The drying apparatus according to claim 1, wherein the passage around the air cushion roller is directly connected with the helical passage. 

1. A drying apparatus for an elongated flexible support which comprises: a. at least one cylindrical air chamber having at least one air inlet and a plurality of air blowoff holes for providing an air cushion for supporting an elongated flexible support which moves continuously aroUnd said air chamber through a helical passage; and b. at least one air cushion roller disposed in the vicinity of said air chamber, said air cushion roller being so arranged that the passage of the support where the support is bridged between said helical passage around the air cushion roller is substantially equivalent to the plane tangent to both of said passages.
 2. The drying apparatus according to claim 1 wherein two or more air chambers are disposed parallel to one another and air cushion rollers are arranged where the support enters, joints and exits said air chambers.
 3. The drying apparatus according to claim 2 wherein a plurality of air cushion rollers are arranged at each portion where the support enters, joins and exits said air chambers.
 4. The drying apparatus according to claim 2 wherein the drying air is conditioned differently for each of said air chambers.
 5. The drying apparatus according to claim 2 wherein the diameters and the lengths of the air chambers are different from each other.
 6. The drying apparatus according to claim 2, wherein the passage of the support is so formed that both the surfaces of said support are dried alternately.
 7. The drying apparatus according to claim 1, wherein the passage around the air cushion roller is directly connected with the helical passage. 